I have been inspired by https://www.printables.com/model/1309310-gopro-mount-for-leki-pole , however it did not work on my LEKI Trigger 3D handle, as LEKI redesigned the system for Trigger 3D handles.

I have utilized https://www.thingiverse.com/thing:4760321 for GoPro mount part and measured and designed the pole mounting part. 

It is mounted like LEKI gate guard - steps in this video How to mount a Gate Guard on your pole | LEKI How-To